As known, gas fireplaces, gas stoves and gas braziers are ignited by an electromechanical ignition device, generally activated by a user, which allows the ignition of a pilot flame at a pilot burner as well as its supervision to ensure that the pilot flame acts as an ignition source for a burner of greater thermal power.
There are suitable valve means for regulating the gas coupled with the ignition device, arranged between the main pipe for the gas and the burners, which are subjected to a thermocouple.
The thermocouple, heated by the flame of the burner, electromechanically monitors the permanent ignition state of the flame. Therefore, possible flame extinction determines a cooling down of the thermocouple and, consequently, the closure of the gas supply to the burner.
In such apparatuses, it is easy to verify if the flame has been extinguished or lost, since it is generally due to a gust of air, a jump in the flue draft, a simple exhaustion of the gas, or similar anomalies.
Therefore, the flame is constantly monitored in the burner in order to avoid damage and dangerous gas leaks. The electromechanical monitoring, by thermocouple, although advantageous from various points of view, has the drawback that the gas supply is not shut off immediately, but occurs only after the cooling of the thermocouple itself. Therefore, there is a danger of the gas escaping without being burnt for a certain period of time before being turned off.
Moreover, during the initial flame ignition step, the user performs a direct manual action in the vicinity of the burner to keep the flame active for a time necessary to heat up the thermocouple. This manual action is risky for the user.
In order to avoid these drawbacks, in recent apparatuses the thermocouples are regulated by special devices that automatically check for the presence of a flame during the ignition step of the gas apparatuses.
Such automatic devices are also supplied by electricity main and by battery means or buffer batteries allowing the apparatuses on which they are installed to operate when the electricity main is not feeding.
Usually the apparatuses, like for example gas fires, are used at locations where there is not a constant supply of electrical power, but rather where the electrical supply varies unpredictably.
Automatic devices with thermocouples are substantially high-energy-consumption devices since they require a high current to maintain the main flow of gas, during the automatic ignition step, to support the flow of gas during the heating step of the thermocouple, and for possible restoring after a flame has been lost.
Therefore, due to the high power required, automatic devices with thermocouples, supplied by buffer batteries, have very low autonomy and are therefore not very efficient, often requiring continuous replacement of the batteries by the user.
This represents a limitation to use of such automatic devices in gas apparatuses.